Polish security services convened a special meeting on Sunday after receiving information about a potential attack on Prime Minister Donald Tusk and Defence Minister Wladyslaw Kosiniak-Kamysz, a spokesperson said.
Special services spokesperson Jacek Dobrzynski said he could not go into details but authorities were treating the threat as "deadly serious".
"We are talking about a high probability of these threats being carried out," he told reporters.
Interior Ministry Spokesperson Karolina Galecka said an email with information about the potential attack had been forwarded to police by the State Protection Service, which is responsible for ministers' security.
While violent crime is relatively rare in Poland, the country is deeply polarised politically and has faced security threats due to its proximity to the war in Ukraine.